Property developers don’t normally resemble Wang Shi. At 58, he is the oldest person to have climbed the highest peaks on all seven continents – including Mt Everest – and to have trekked to both poles. Next year, he will be climbing Everest again. And he then plans to sail around the world.

Nor is he any old property developer – he’s the biggest one in the world. His company, China Vanke, builds 68,000 homes a year. And his adventures have turned him green, because every time he has gone back to the mountains he has found less ice and snow. As he told me: “Global warming is my personal experience.”

We were talking en route to Copenhagen, travelling the environmentally friendly way on a day-long train journey from Brussels. The one-off Climate Express, laid on by the International Rail Union, ran entirely on renewable energy.

As it clattered through Germany, Mr Wang told me that it was his concern about the felling of forests that led him to use steel shuttering, instead of the traditional wood, when pouring concrete. This was cutting his use of timber by 87 per cent, and would save seven million cubic metres of it a year. He’d also cut his firm’s energy use by 20 per cent, water by 63 per cent and waste by 91 per cent.

He is increasing the installation of solar electric panels 10-fold every year, and hopes to use wave power on projects near the coast. He’d better be careful, or he might end up giving builders a good name.